To assess the effects on wildlife a Habitat Evaluation Procedure (HEP) was conducted on Satsop Forest (then known as the Satsop Nuclear Site) and completed in 1994. This procedure was created by US Fish and Wildlife Service as an accounting system to assess the effects of projects on wildlife habitat. Wildlife habitat is used as "currency" with changes due project activities and/or mitigation are compared. Habitat quality and quantity are estimated using Habitat Suitability Index (HSI) models and Habitat Unit (HU) calculations. The process follows the following steps:
The following is a brief over view of the original HEP and the automated HEP. For more in depth information contact Kevin Ceder via e-mail or phone at 206.543.0827.
Original HEP
Cover Typing
Cover types were
originally delineated from aerial photographs based on apparent
vegetation changes. Maps were created using CAD based on the cover
typing. The following cover types were used:
Conifer | C1 - Early successional | C2 - Pole | C3 - Mature | C3T - C3, thinned | C4 - Late successional | C4T - C4, thinned |
Deciduous | H1 - Early successional | H2 - Sapling | H3 - Mature | |||
Mixed | M1 - Early successional | M2 - Pole | M3 - Mature | |||
Palustrine | PE - Pal. emergent | PS - Pal. shrub | PF - Pal. forest | |||
Other | G - Grass | B - Brush | BA - Barren | P - Ponds | D - Developed |
All the cover types were defined based on various measures. For definitions click on the cover type. Changes in the cover types was estimated by the team that performed the HEP. Thus a cover type would be "allowed" to develop in a certain trajectory. For each target year these estimates were made and acreages calculated from a map.
Model Selection
Five models were
selected to track different habitat types. These were:
Model Application
All
models used were published between 1978 (spotted towhee) and 1991
(black-tailed deer) and designed for all cover types, with the
exception of the spotted towhee model that is designed for deciduous
woodlands. The Cooper's hawk model has since been updated but
it is being applied as it was in the original HEP. During the
original HEP it was decided that the models would be applied to
specific cover types to track changes in those cover types. The
were applied as follows:
Data Collection
Each species
model has different habitat requirements. Thus data collection
needed to be done accordingly. The following attributes, which
can be broken down into tree-based and non-tree-based attributes,
were measured in 1991:
Tree Based
Non-tree-based
These attributes were averaged for each cover type. These values were then used for HSI and HU calculations.
Target Year Selection
The HEP
uses target years to estimate the habitat impacts of a project.
In essence a few discrete snapshots in time are examined to assess
the effect of the project. The years chosen were:
Mitigation Alternative Creation
Five mitigation alternatives
were created for the Satsop Nuclear Site:
Impact Assessment
For each target year
for each alternative Habitat Suitability Index (HSI) values were
calculated for each cover type. These numbers were then used to
calculate the number of Habitat Units (HU) for each species at
each target year. The HU's were then used to calculate Average
Annual Habitat Units (AAHU) for each species for each alternative.
The AAHU's under each mitigation alternative were then compared
for selection of a preferred alternative.
Automation of the HEP
To help develop more management alternatives for Satsop Forest the HEP process was automated in the Landscape Management System (LMS). This was done by coding the cover typing rules, HSI models, and HU and AAHU calculations into LMS and using an improved timber inventory. This was done using the following process:
Once this was done input data for the HSI models could then be calculated by programs running in LMS. This was very straight forward for tree-based variables. Simply a direct calculation. For non-tree-based variables data from the 1991 HEP data collection that was related to each cover type was used. The cover type was determined based on the cover type rules and an attribute value assigned to that cover type. These attribute values were then used to calculate HSI for each species for each stand. These figures were then used to calculate the HU's for each stand and the landscape for each species as well as the AAHU's for each species for the life of the management alternative.
Data Collection
During the summer
of 1998 a timber inventory of Satsop Forest was conducted.
This was necessary to get tree-based data of sufficient quality
to create a n LMS portfolio for LMS. The attributes measured
were:
These measurements were done with nested plots. A variable radius plot using a BAF 20 or BAF 40 prism depending on tree sizes for trees and snags with DBH >5" with a 1/300th acre fixed radius plot from the same plot center for trees and snags with DBH <5" and downed wood. Height, crown ratio, and breast height age were measured for the largest tree on each plot for site index calculations. Heights and crown ratios for the remaining trees were estimated using the height dubbing function in the Forest Vegetation Simulator (FVS) growth model.
Portfolio Creation
A portfolio for LMS
brings together a variety of landscape data. These are:
Calculating the stand level acreage, slope, aspect, and elevation required creation of new GIS data for Satsop Forest. This was done from CAD maps created for the original HEP with calculations made using ArcInfo functions created by Phil Hurvitrz, the GIS guru at the College of Forest Resources, University of Washington.
Cover Type Coding
Creating the cover typing code
from the cover type rules uses a system of "if" statements once the
values for all necessary attributes for each stand have been calculated by LMS.
Each stand is then assigned a cover type for each period of the management cycle.
When initially running the cover typing rules some issues were noted.
Some stands were falling all the way through the cover typing rules without
being assigned a cover type code. Some minor modifications of the rules
were made. These can be seen on the HEP
cover typing page.
Model Coding
HSI model
are published in the form of graphs. Input values are found
on the x-axis, a vertical line is drawn to the line or curve on
the graph, and a horizontal line is drawn to the y-axis for a
HSI value, ranging from 0.0-1.0 for that attribute. The
models used contain three to five attributes. These are
then multiplied and raised to a power, depending on the number
of variables, to yield a final HSI ranging from 0.0-1.0.
For more information see: http://www.nwrc.gov/wdb/pub/hsi/hsiindex.html
HSI, HU, and AAHU
Calculations
HSI values
are calculated for each species using tree-based values calculated
directly from current and projected forest inventory by LMS and
cover type averages of non-tree-based values related to cover
types assigned using current and projected inventory information.
These values are calculated for each species for each stand on
the landscape. The HSI value is then used to calculate HU's
by multiplying the HSI by the acres of the stand then summing
them for all the stands in the habitat cover types for that species.
AAHU's are calculated by averaging each period's total HU's for
each species over the life of the management plan.
Updated 20/12/2000 by Kevin "thujaman" Ceder